1. Field of the Invention
The invention relates to a method and an apparatus for handling pipes, such as rods and drilling strings, in drilling rigs and drilling installations for sinking boreholes, in particular on hydrocarbon reservoirs.
2. Description of the Related Art
Boreholes on hydrocarbon reservoirs are generally sunk discontinuously since, after a joint length has been drilled, the drilling operation has to be interrupted in order to attach a further joint, with which the drilling operation can then be continued. In addition, the disassembly of the drilling string or the installation and disassembly of bore hole casings are also discontinuous, since the operation has to be interrupted each time in order to join the appropriate pipes or drilling rods to the drilling string or the casing string, or to detach them. If drilling strings comprising two or three rods or pipes are put together or separated again into individual rods or pipes, this is also carried out over the bore hole. Therefore, during this operation, drilling cannot be continued, nor can further drilling joints or casings be drawn. Normal drilling rods reach a length of approximately 9 meters, a triple drilling string (triple stand) reaches about 27 meters.
Because of increasing pressure on costs, there is a requirement of the operator of drilling installations to replace the discontinuous operation of sinking boreholes or pulling drilling strings and casings by a quasi-continuous sequence.
In the stationary onshore drilling installation UTB-1 (Forschung, Planung und Betrieb [Research, Planning and Operation], Volume 18, 1993), handling systems were used with which drilling strings were pivoted over the bore hole not by means of the hook of the drilling installation itself but by a self-contained joint handling system.
In addition, pipe racking systems are known, for example those from Maritime Hydraulics, which feed drilling strings to the drilling installation by means of three-arm systems or a bridge crane on the racking platform. The drawback with this joint handling system is that the derricks have to be suitable, in particular with regard to their static strength and their weight, to integrate these handling systems. Retrofitting or fitting them to already existing, in particular lightweight, derricks belonging to drilling installations is not possible with these handling systems. In addition, these handling systems entail high investment costs.
It is therefore an object of the invention to specify a handling method and an apparatus for handling drilling strings with which already existing drilling installations, in particular those of lightweight design, can be retrofitted, or else to equip new drilling installations with them cost-effectively. In addition, it is an object to prepare drilling strings in an operation parallel with the drilling operation, in order to accelerate the installation and therefore the drilling operation as a whole.
The apparatus according to the invention for handling pipes and drilling strings in a drilling installation having a steelwork structure, e.g., a derrick with a set-down platform, a working platform, a lifting device, a drill drive and a pipe connecting device is characterized in particular by the fact that there is arranged on the drilling installation a wireline, a two-axis crane which is connected to the wireline and to the steelwork structure, and an extension element, which is arranged on the outside of the racking platform and has a passage to the racking platform, and by the fact, that a set-down and make-up device, arranged beside or on the working platform, is provided for vertical pipes, it being possible for the set-down and make-up device to be accessed by the wireline.
With the apparatus according to the invention, there is the possibility of retrofitting existing drilling installations in order to increase the drilling installation performance and working safety by means of the parallel preparation of double or triple drilling strings, since the handling and make-up time runs in parallel with the normal drilling time, and therefore the overall time for the drilling operation is shortened.
In addition, it is advantageously possible that the individual rods or drilling strings can be sorted during the drilling activities, without being exposed to the risk of colliding with the rotating drilling string.
One advantageous refinement of the invention provides for the wireline to comprise a winch, one or more turn rollers, a lifting wire and a lifting aid.
The set-down and make-up device for pipes advantageously has one or more rat holes and/or set-down boards, and one or more holding elements and/or guide elements, which are preferably connected to the working platform. These holding elements and guide elements secure the rods or pipes in their upper region against falling out.
In a further preferred refinement, the particularly cost-effective and flexible make-up device arranged on the set-down and make-up device preferably comprises a suspended crane on which make-up tongs are suspended.
Particular preference is given to the design of a set-down platform which comprises a frame with two opposite sectors, in each case a number of racks being arranged in the sectors and a central web (monkey board) being arranged between the two sectors. It has been shown that part of the central web should be designed to fold and/or pivot, in order to be able to sort or to move the joints within the racking platform.
A further particularly preferred refinement of the invention provides for a gripper to be arranged on that side of the central web or the set-down platform which faces the steelwork structure. Said gripper can comprise two gripper arms which grip around the joint or merely have holding elements. This gripper constitutes a transfer point for the joint between the racking platform on the one hand and the drilling area on the other hand.
In a preferred variant, a joint chute or ramp is arranged on the set-down and make-up device, so that drilling rods can be introduced into the apparatus according to the invention independently of the chute which is normally present.
The method according to the invention of handling pipes and drilling strings in drilling installations is characterized by the following method steps:
a) the lifting aid on the lifting wire is positioned above a transfer point, and
b) at least one rod is set down in the set-down and make-up device, and
c) a further rod is drawn by means of the lifting aid and is positioned over a rod located in the set-down and make-up device and then
d) said device is lowered slightly, so that the collar and pin of the tool joints of the two rods can interengage, and
e) the two rods are then firmly connected to each other, and then
f) the drilling string of two rods is placed by means of the lifting aid onto a set-down space on the working platform, between two racks of the set-down or racking platform or in a gripper or holder, or is moved so close to the drill drive that the drilling string can be taken over by the elevator.
A further advantageous variant of the method is characterized by the fact that, for the purpose of producing a drilling string from three rods, between method steps b) and c) at least one second rod is set down in the set-down and make-up device, and by the fact that, after two rods have been joined to form a drilling string in accordance with method step e), said drilling string is positioned over the rod still positioned in the set-down and make-up device, and then method steps d) and e) are carried out again.
It is particularly advantageous for the transfer point selected to be the upper end of a joint chute or ramp. As a result, the rod can be connected directly to the lifting aid without needing a further device, such as a pneumatic hoist.
The refinement of the method according to the invention which provides for the connection in method step e) to be made by means of make-up tongs, the make-up tongs enclosing the upper tool joint of the lower rod and the lower tool joint of the upper rod and screwing them together.
By means of the method according to the invention, the production or preparation of one or more drilling strings can be carried out in parallel with drilling, the steel structure of the derrick being used, without impairing or delaying the drilling operation. In addition, only a small additional area is needed.
The procedure in which the method steps a) to t) are carried out in the reverse order, the rods in a drilling string being separated instead of joined, likewise leads to considerable time saving.
The pivoting or folding or displaceable front part of the central web of the monkey board frees up adequate space for the rods or drilling strings to be moved from one sector of the racking platform into the other sector of the racking platform with the aid of a lifting aid and using the two-axis crane.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.